> On 13-Oct-2017, at 10:52 AM, Anil Vishnoi <[email protected]> wrote:
> 
> 
> 
> On Thu, Oct 12, 2017 at 9:34 PM, Shuva Kar <[email protected] 
> <mailto:[email protected]>> wrote:
> 
>> On 13-Oct-2017, at 9:20 AM, Abhijit Kumbhare <[email protected] 
>> <mailto:[email protected]>> wrote:
>> 
>> First of all - yes - CSIT needs to be added for the hitless resync. Secondly 
>> hitless resync is different from bundles. Hitless resync is a reconciliation 
>> mechanism which uses bundles in order to be - errr hitless. The basic idea 
>> is that the switch will continue using the original flow table/s, the 
>> controller replays the flows/groups from the config into a bundle, the 
>> switch receives the bundle in a copy of flow table/s - and once the bundle 
>> programming is done makes the copy active. Basically to avoid datapath 
>> disruption during reconciliation.
>> 
>> The bundles feature as present is available from OVS 2.6 and above. 
>> 
>> Gobinath has added a reconciliation framework which would allow to plug in a 
>> different resync mechanism in the patches:
>> 
>> https://git.opendaylight.org/gerrit/#/q/owner:gobinath%2540ericsson.com+status:merged+project:openflowplugin
>>  
>> <https://git.opendaylight.org/gerrit/#/q/owner:gobinath%2540ericsson.com+status:merged+project:openflowplugin>
>> 
>> I don't believe he has actually added the hitless resync (looking at the 
>> patches) - I will ask him to shed more light.
>> 
>> About:
>> 
>> - How do we verify this feature? is there a way to check bundle programming 
>> has really happened?
> 
> As Abhijit rightfully mentioned, Hitless resync is a feature and ofp bundles 
> is a way of implementing the same. To test this implementation, we need to 
> 1. enable the hitless resent feature, its not enabled by default,
> 2. Provision some flows on a set of switches/end-points
> 3. Ensure that there is traffic flowing through them, ping could be used
> 4. Cause a tcp disconnect between the controller and the switches and then 
> connect back
>  There should be no blip in traffic . The only thing to ensure is that Arp 
> entries on the switches do not timeout when the control plane is dissected.
> ​Not sure, if this is really a right test to do or not. Because traffic blip 
> will depend on when bundle is committed on each switch. You can use bundle to 
> commit all the flow/groups atomically, but doing it across the switches is 
> controllers job, and you can still see the disruption in the traffic. I think 
> the only test we can do that will verify that bundle based flow/installation 
> is working is, to run all the test suits with 
> bundle-based-reconciliation-enabled=true. So ideally after enabling bundles, 
> we should not see any behavioral change in the existing tests.​ 
> 

Absolutely correct. I was speaking from an E2E perspective, my bad! Wearing the 
wrong hat yet again !!!

Correct ! Behaviourally there should not be any change before and after 
enabling the hitless resync. The applications on the controller should take 
care of pushing the flows/groups across the switches on sensing a switch 
connect. 

From the plugin perspective we can just check if the bundle based 
provisioning/deprovisioning is working correctly.

> Hope that helps :)  
> 
>> 
>> We would need to have tests verifying reconciliation with zero datapath 
>> disruption - so we will need to think about it a bit.
>> 
>> 
>> On Thu, Oct 12, 2017 at 1:15 PM, Anil Vishnoi <[email protected] 
>> <mailto:[email protected]>> wrote:
>> 
>> 
>> On Thu, Oct 12, 2017 at 10:53 AM, Luis Gomez <[email protected] 
>> <mailto:[email protected]>> wrote:
>> I have few questions on this feature:
>> 
>> - Is this feature enabled by default?
>> ​Yes, its a feature, but as of now no application is basically using it. We 
>> do have a sample application that shows  how user can use this feature.
>> https://github.com/opendaylight/openflowplugin/tree/master/samples/sample-bundles
>>  
>> <https://github.com/opendaylight/openflowplugin/tree/master/samples/sample-bundles>
>> ​ 
>> - Which OVS version supports bundles? I believe we currently use 2.5.2 in 
>> latest tools VM
>> ​I believe 2.5.2 don't have support, but i am not sure. ​ 
>> - How do we activate bundle programming? is it enough to push a bunch of 
>> flows/group to FRM using REST?
>> ​I will get back to you on that.
>> - How do we verify this feature? is there a way to check bundle programming 
>> has really happened?
>> ​Bundle failure generates the error, but i think the easiest way probably is 
>> to program different set of flows with bundle and verify that all the flows 
>> are present in the switch.
>>  
>> 
>> BR/Luis
>> 
>> 
>>> On Oct 12, 2017, at 10:26 AM, Anil Vishnoi <[email protected] 
>>> <mailto:[email protected]>> wrote:
>>> 
>>> No, there is no CSIT test for bundles.
>>> 
>>> On Thu, Oct 12, 2017 at 10:15 AM, Jamo Luhrsen <[email protected] 
>>> <mailto:[email protected]>>wrote:
>>> it's the thing that uses openflow bundles. I didn't follow the dev cycle
>>> with it, but I get the sense that it works now.
>>> 
>>> https://wiki.opendaylight.org/view/OpenDaylight_OpenFlow_Plugin:Hitless_resync
>>>  
>>> <https://wiki.opendaylight.org/view/OpenDaylight_OpenFlow_Plugin:Hitless_resync>
>>> 
>>> JamO
>>> 
>>> On 10/12/2017 10:04 AM, Luis Gomez wrote:
>>> > What is hitless resync in the OF plugin context?
>>> >
>>> >> On Oct 12, 2017, at 8:22 AM, Jamo Luhrsen <[email protected] 
>>> >> <mailto:[email protected]>> wrote:
>>> >>
>>> >> Hi OFP,
>>> >>
>>> >> We talked a little about this hitless resync feature from 
>>> >> openflowplugin. It's of
>>> >> interest to netvirt. I'm wondering if there are any CSIT jobs that 
>>> >> validate it in
>>> >> the openflowplugin CSIT jobs?
>>> >>
>>> >> We'll be adding some netvirt test cases that will also test it, but just 
>>> >> from a
>>> >> higher level than maybe it would be tested at your level.
>>> >>
>>> >> Thanks,
>>> >> JamO
>>> >
>>> _______________________________________________
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>>> <https://lists.opendaylight.org/mailman/listinfo/openflowplugin-dev>
>>> 
>>> 
>>> 
>>> -- 
>>> Thanks
>>> Anil
>> 
>> 
>> 
>> 
>> -- 
>> Thanks
>> Anil
>> 
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> 
> 
> 
> 
> -- 
> Thanks
> Anil

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